The present invention relates to a first agent for oxidation hair dye containing a carbonate and a method for stabilizing a color tone of hair dyed by an oxidation hair dye composition.
Hair dye compositions capable of exhibiting effects upon mixing plural chemicals are known. As such hair dye compositions, there are known oxidation hair dye compositions constituted of a first agent containing, for example, an alkali agent and an oxidation dye and a second agent containing an oxidizing agent, for example, hydrogen peroxide. The oxidation dye can be properly chosen among known dyes from the viewpoints of desired color, lightness, chroma, and the like. For example, in the field of fashion color where high lightness and chroma are in general required, an oxidation hair dye composition in which a prescribed amount of m-aminophenol, 5-amino-o-cresol, or α-naphthol is compounded as an oxidation dye is used.
The alkali agent not only accelerates an action of the oxidizing agent to be contained in the second agent but also swells the hair to improve permeability of the dye into the hair, thereby improving a hair dyeing power. There have hitherto been known ammonia and the like as the alkali agent to be used for the oxidation hair dye composition. However, there was involved such a problem that if a compounding amount of ammonia is increased, an irritant odor is accompanied therewith. There have hitherto been, for example, known oxidation hair dye compositions disclosed in JP-A-2001-206825, JP-A-2001-328926 and JP-A-2008-127343. According to JP-A-2001-206825, JP-A-2001-328926 and JP-A-2008-127343, by using ammonia and a carbonate in combination as the alkali agent, it is contemplated to not only make the compounding amount of ammonia lower than before but also improve hair dyeing power.